레드머드 및 알칼리성 혼화제 혼입에 따른 모르타르의 공학적 특성 평가

초록

This study evaluated the engineering properties and microstructural changes of mortar based on the red mud substitution rate and alkaline admixture incorporation. The experimental results suggested that increasing the red mud substitution rate progressively decreased mortar flow due to the rapid absorption of mixing water. The mechanical strength also declined, dropping sharply at a 40% substitution rate. Conversely, the incorporation of the alkaline admixture improved the compressive strength, enabling 10% and 20% substitution mixtures to achieve strength levels comparable to the plain mixture. In water absorption tests, all mixtures showed rapid water absorption up to the initial six hours via capillary action, after which the rate stabilized. At a red mud substitution rate of 20% or less, the admixture enhanced watertightness, reducing the absorption rate. At 30% or more, however, the absorption rate increased as degraded admixture dispersion led to capillary pore formation. Furthermore, MIP analysis showed that while red mud substitution increased the overall porosity, the incorporation of the alkaline admixture significantly decreased the total intrusion volume, porosity, and average pore diameter by promoting cement particle dispersion and hydration acceleration.

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